This invention relates to a composite body that is electrically insulating and is composed of metal particles dispersed in a continuous glassy matrix to form a secondary phase. The metal particles are so shaped and oriented as to provide a unique combination of good thermal conductivity and electrical insulation.
The advantages of combining the high temperture properties of ceramics with the unique properties of metals have been apparent. Their potential has given rise to extensive studies and the development of a diverse array of materials.
There is still, however, need for a material combining good heat conductivity with the normal capability of electrical glasses and ceramics to insulate against both AC and DC currents. Recent strides in electronic component development have focused increased attention on this need. For example, light emitting diodes (LED) tend to generate substantial thermal energy during operation. If this energy is not adequately dissipated, the life of the device may be limited and/or the output power diminished.
Another component that is very susceptible to thermal damage is the integrated circuit chip in high speed digital integrated circuits. Again, operating life of the chip may be severely curtailed, unless thermal energy is dissipated as it is generated during circuit operation.
Most dielectric materials tend to be poor thermal conductors. A standard material used today for encapsulating, or packaging, electronic components is alumina, despite its recognized poor heat conductivity characteristic. Beryllia has better thermal conductivity than alumina, and has been proposed as a substitute. However, its toxic nature makes its use undesirable at best.